Known spacer strips consist preferably of silicone foam with which up to about 30% of a drying agent (which in the following refers for short also to a mixture of a plurality of drying agents) has been admixed. For the drying agent to achieve its purpose of removing moisture from the inside space between the panes, the silicon foam is of an open-pore structure. Therefore a (water) vapor-sealing layer is needed on the outside of the spacer strip, which also should be resistant to UV radiation, but should not prevent the strip from being bent to a short radius of curvature, or from being shaped to form an angle (following a punching-out of a corner wedge) in the corners of an insulating glass unit. Although a very thin aluminum layer, as usually deposited by sputtering, does not prevent the spacer strip from being bent, or shaped to form an angle, it nevertheless has a tendency to form micro-cracks that adversely affect sealing to vapor diffusion.
Because the known spacer strip consists of silicone foam combined with a drying agent, it is of only limited dimensional stability. Apart from this, only relatively small amounts of drying agent can be mixed with the silicon resin, because otherwise both the strength and the elastic properties of the strip are impaired.
Known insulating glass units have a similar spacer. The similar spacer consists of a hollow synthetic resin section that is preferably reinforced with glass fibers and contains a drying agent that communicates with the inside space of the insulating glass unit via perforations in the spacer.
Another similar spacer is known which consists of a synthetic-resin section, e.g., of PVC, filled with a drying agent.